Other Types of Liquid Chemicals - Video Tutorials & Practice Problems
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1
concept
Heavy Metal Compounds
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2m
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in this video, we're going to begin our lesson on other types of liquid chemicals used for controlling microbial growth, starting with the heavy metal compounds. And so heavy metals are really just medals with relatively high densities, atomic numbers or atomic weights and heavy metals include the metals, silver, arsenic, zinc and copper, which can be used as disinfectant at very low concentrations. And the reasons these heavy metals need to be used at low concentrations is because at high concentrations they're actually extremely toxic to humans and they can also pollute natural waters like lakes and oceans. And so it's best for them to be used only in low concentrations. Now these heavy metals actually have the ability to de nature proteins which recall just means that it's going to cause the proteins to lose their shape and lose their function. And these metals can do that by interacting with the salt hydro groups on proteins or the S. H. Groups on proteins and that once again will change their structure and that will denature the protein now, specifically silver containing antiseptics can be used to prevent infections on the skin of humans. And so if we take a look at our image down below notice, we're showing you an image of these heavy uh metals which can once again be used as liquid chemicals to controlling microbial growth. And we're showing you a bunch of different examples of heavy metals such as copper, zinc, arsenic. And over here we're showing you silver and so silver containing antiseptics once again can be used as antiseptics, this treat wounds or infections on the skin. And so this year concludes our brief introduction to the use of heavy metal compounds as liquid chemicals for controlling microbial growth. And we'll be able to get some practice and learn more about other types of liquid chemicals as we move forward in our course. So I'll see you all in our next video
2
Problem
Problem
Heavy metals are no longer used to prevent microbial growth in cooling water primarily because:
A
Antibiotics are cheaper.
B
Other chemicals were shown to be much more effective.
C
Microbes developed resistance to these metals.
D
Their use contributes to serious pollution of natural waters.
3
concept
Phenolic Compounds
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2m
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in this video, we're going to continue to talk about other liquid chemicals for controlling microbial growth by briefly focusing on phenolic compounds. And so these phenolic compounds or just phenolic for short as their name implies are really just a class of chemicals that are derived from a molecule known as fennel. And so this final molecule really just consists of a benzene ring bound to a hydroxyl group or an O. H. Group. And so if we take a look at our image down below, notice on the left hand side over here we're showing you an image of the molecule phenol and again this molecule phenol consists of this benzene ring that you see highlighted here in green with a hydroxyl group or an O. H. Group attached. And again these phenolic sor phenolic compounds are going to be molecules that are derived from this final molecule. Now it turns out that a scientist of the name joseph Lister was actually the first to employ fennel as an antiseptic or a disinfectant. And so down below what we have is an image of joseph Lister. Now since joseph Lister first employed these phenols, they have been used commonly in many different types of products. And in fact the oral antiseptic. Listerine was actually named after joseph Lister. Also phenolic are the active ingredient in the common household disinfectant called Lysol. And so if you use Lysol in your house again to disinfect uh then you can remember that there are phenolic in there. And so down below what we have is an image of this bottle of Listerine. The oral antiseptic and also a bottle of the Lysol, which again you could use in your house as a disinfectant. Now the way that these phenolic are able to control microbial growth is because the phenolic are able to disrupt cytoplasmic membranes and denature proteins, and so by doing so, they are able to kill the cells and control the microbes. And so this year concludes our brief introduction to the phenolic compounds or Alex and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.
4
concept
Peroxygens
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4m
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in this video, we're going to continue to talk about other liquid chemicals used for controlling microbial growth by specifically focusing on paroxetine. Chins. And so proxy jin's are a group of molecules that serve as strong oxidizing agents. And so recall from our previous lesson videos that oxidizing agents are going to cause other molecules around them to become oxidized or lose electrons. And these proxy jin's that serve as strong oxidizing agents can actually be used as sterile ins when used appropriately to kill all microbes. Except for prion of course. However, they can also be really, really toxic to humans at high concentrations and so they must be diluted and used at low concentrations in order to be used safely. Now some common examples of poor oxygen's include parasitic acid whose chemical formula is C two H 403 and hydrogen peroxide, whose chemical formula is H 202. Now parasitic acid, which is again, C2H403 is actually a lot more potent, a lot more powerful of a chemical disinfectant and sterile in than hydrogen peroxide is. However, parasitic acid, even though it's more potent, it's also more irritating to the skin and the eyes. So it has some advantages and some disadvantages as well. Now hydrogen peroxide is commonly used at low concentrations once again because at high concentrations it can be toxic and it's used at low concentrations specifically on the skin to prevent infections. And so some of you that may have had injuries in the past may have used hydrogen peroxide to help control the microbial growth around your injury. Now, these poor oxygen's prior acetic acid and hydrogen peroxide are going to disrupt cytoplasmic membranes and they're going to denature proteins as well. And that is really how they can damage microbes and destroy microbes for controlling microbial growth. Now, it's also worth noting from our previous lesson videos, you should recall that some microbes have the enzyme called catalyst and catalyst is the enzyme that will convert hydrogen peroxide to water and oxygen. And so that is basically converting this hydrogen peroxide into chemicals that are not really toxic to the microbe. And so hydrogen peroxide is a less effective disinfectant than parasitic acid, because some microbes that have this enzyme catalyst are able to convert it to water and oxygen and therefore they're able to survive in lower concentrations of hydrogen peroxide. And so, if we take a look at this image down below, we can see these per oxygen's on the left hand side, we're showing you the chemical structure for parasitic acid. Uh and again, you can see that its chemical formula C two, H 403, and its chemical structure is right here, this little corner here represents a carbon atom. Then what we have is the chemical structure for hydrogen peroxide, whose chemical formula is H202. And you can see its structure right there. And so this is a bottle of hydrogen peroxide that you may have in your home for treating some of your wounds. And so, uh again, uh, some cells have this enzyme called catalyst, which can convert the hydrogen peroxide into water and oxygen gas. And so this is why hydrogen peroxide is not as potent, um as parasitic acid is. But this year concludes our brief lesson on Prayer oxygen's and how they are used as liquid chemicals for controlling microbial growth. And we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
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Problem
Problem
Which chemical are all phenolic chemicals a derivative of?
A
Hydroxyl.
B
Ethanol.
C
Aldehyde.
D
Phenol.
E
Benzene.
6
Problem
Problem
Which of the following is not considered a peroxygen?
